Effect of treatment with magnesium and potassium on mortality and reinfarction rate of patients with suspected acute myocardial infarction.

The aim of the study was to test whether magnesium and potassium administration can decrease both early and late cardiac event rates in 355 patients with suspected acute myocardial infarction (AMI). The study was conducted by a primary and secondary care research centre as a randomized, initially double-blind comparison for 4 weeks followed by a single blind period for 2 years. Patients with definite or possible AMI and unstable angina based on World Health Organization criteria were assigned within 24 hours of infarction to different groups. Treatment was administered for 3 days through intravenous infusion with either 8.12 mmol/day Mg (group A, n = 81), 10.49 mmol/day K (group B, n = 77) 10% dextrose solution (group C, n = 87) or a placebo containing 2% dextrose solution (group D, n = 81). After discharge from the hospital all groups were advised to follow a fat-reduced diet. Groups A, B, and C were also advised to take magnesium hydroxide or potassium chloride orally. Comparison of groups A and B with group D over 2 years indicated that treatment with magnesium or potassium was associated with increased (p < 0.05) serum magnesium and potassium, and significant reduction in the incidence of cardiac events (22 and 24 vs 41 patients), total mortality (9 and 10 vs 20 deaths), and ventricular ectopics (17 and 21 vs 44), respectively, in the groups. Group C showed no significant benefit. It is possible that magnesium and potassium infusion immediately after AMI and addition of Mg and K salts to the AMI regimen may enhance tissue levels of these cations, leading to significant reduction in complications and mortality after 2 years.